Yieldable coupling



LE ROY LANGFORD YIELDABLE COUPLING Filed July 25, 1942 Aug. 3, 1943.

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INVENTOR. zekoy lzfford ATTORNEYS Patented Aug. 3, 1943 1 2,325,780 IELDAB urie s Le Roy Langford; Toecoa, Ga., assignor to R. G.

Le Tourneau, Inc., StocktomCalif a-corp'oration I Application 'Jn'ly 25, 1942, Serial No. 452,257 V V 2zClairns. (01. 64-29) This invention relates in general to ayieldable coupling adapted for connection between adja cent ends of a drive and a driven shaft, andiin I particular the invention is directed to, and it is an object to provide, a yieldable coupling adapted for connection between the drive shaft of a machine tool actuating motor and a driven shaft of said tool; the coupling being designed to release or overrun in the event of an excessive load on the driven shaft whereby to prevent damage to both the motor and driven parts of the tool.

The yieldable coupling hereinshown and described is especially designed for connection be tween the drive motor and the adjacent driven shaft of a lathe tool slide drive mechanism, such as is shown in copending application for United States patent, Serial No. 391,736, filed May 3', 1941. 1

Another object of the present invention is to provide a yieldable drive coupling for adjacent shaftswhich include a radial disc having a hub adapted for connection with on shaft, and as sleeve rotatably seated in an axial concentric bore in said disc and adapted for connection with the adjacent end of the other shaft; there being spring pressed detent mechanism between said disc and sleeve arranged to normally prevent rel ative rotation therebetween but operative to automatically permit such rotation inthe event of F the load on the coupling exceeding a predeterf mined amount.

An additional object of the invention is to pro- 7 V vide a yieldable coupling, as in the preceding paragraph, in which said detent mechanism includes spring pressed tapered detents or dogs car-- ried by the disc and seating in correspondingly formed grooves-in the sleeve portion; there'being means to adjust the spring pressure on said dogs and thereby regulate the load on the coupling required to free the dogs from the grooves and cause the coupling to overrun.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for whichit is designed.

These objects are accomplished by means of such structure and relative arrangement of parts i screw 5.

operating 'dogs, detached from the remainder of thedevice." Y f Referring now moreparticularly'to thejch'a'racters of reference on the drawing, the device is adapted for connection in driving relation between the adjacent ends of alined shafts land2;

- one of said shafts'being the drive shaft and the other the driven shaft. 7

The coupling comprises disc 3 of substantial diameter and width disposed radially relative to said shafts and concentric thereto; said ,disc including a. hub 4 into which the adjacent end of shaft l snugly projects, -the end portion of the shaft beingsecured in the hub by means of a set The disc is formed with a circular bore 6 of substantial depth which opens to the face of the disc opposite hub 4.- A sleeve 7 snugly but'rotatably seats in bore 6; said sleeve projecting some distance beyond the disc. The adjacent end "of the other shaft 2 projects into sleeve 5 and is secured therein by means of a set screw 8.

The disc 3 is formed with a plurality of circumferential and symmetrically spaced radial to the bore 6. A detent or dog 50 is slidably disposed in each passage 9, and at its inner end is symmetrically tapered in a plane circumferentially of the sleeve. These dogs seat in V- shaped, longitudinal grooves H of matching configuration formed in the sleeveand :opening to the periphery thereof. I

An adjustment screw [2 is threaded in the outer end of each passage 9 terminating at its inner end short of the corresponding dog H3; there'being a compression spring l3 engaged under compression between each adjustment screw and dog. A lock nut M is threadedon the outer end of each adjustment screw and seats against the periphery'of disc 3.

In operation, the adjustment screws l2 are run down so that an equal spring pressure is imparted to each of the dogs and to such extent that the dogs normally remain in the sleeve grooves holding the disc and sleeve in locked or driving relation, but yield and escape said grooves in the event oi excessive load on the driven shaft, whereby the disc and sleeve overrun relative to each other during the period of the excessive load, but automatically return to locked or driving relation when said load is relieved. The use of replaceable shear pins or other similar elements as now used in safety drive couplings is entirely eliminated, thus avoiding considerable repair and maintenance expense as well as time V loss. Also, the dog and cooperating groove arrangement allows for a certain amount of axial adjustment of the shafts relative to each other without disturbing the functioning of the device.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein. 7

Whilethis specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention; asdefined by the appended claims. 7 A

Having thus described my inventiOn;: What 1 claim as new and useful and desire to secure by v Letters Patent is:

1. A yieldable drive coupling adaptedfor connection between adjacent ends of alined shafts, pri in a adia l dispos d d sc o subs antial thickness; an axial hub projecting *frorn'the disc adapted o be. secure on. e aelacent e of o aft, the disc avi g n axia here pen leasably seat, whereby the disc and sleeve are nonnally in driving relation; said sleeve being adjustable axially for a limited extent and relative to the disc, said recesses being longitudinal rooves. -f;

2. A couplingras in claim lrincluding a setscrew threaded through the sleeve and adapted 'to engage the portion of said other shaft within said sleeve; said longitudinal grooves being of substantially greater length than the corresponding dimension of the dogs.

- LERGY LANGFORD. 

